Fuel gauge reading incorrectly

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67cudaGuy

67cudaGuy

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Hey all,

I'm having an issue where my fuel gauge is reading empty when the tank is still half full, I installed a new Napa sending unit and a RTE limiter in my duster with a rally dash. I tested the gauge with the old sending unit (float was rusted) and it read correctly when I adjusted the float manually. Would this mean the new sending unit is no good? Thanks
 
Yup. All new aftermarket fuel sending units are made by the same outfit and reboxed and sold by many. I'm surprised Napa had it from any source. My son has bought at least 3-4 of them, one 80 Dodge d100, 87 ramcharger and 2 c body ones, one for each of the 72 fury wagons he's had. He finally got the current 72 reading right only after he put the NOS sending unit that I found for him into it. They all read empty when there's really a 1/2 tank of gas left. Every damn aftermarket one he's had. Pure garbage and lots of false hope for us guys playing with older cars
 
Do yourself a favor and put a new float on the old sending unit and reinstall it.
Your other option is to install a MeterMatch unit and hope you can get it calibrated decently.
Of course, you could order one from Australia, as they have the only manufacturer I've heard of with an accurate reproduction.
Fuel tank sending unit
 
volaredon said:
Yup. All new aftermarket fuel sending units are made by the same outfit and reboxed and sold by many. I'm surprised Napa had it from any source. My son has bought at least 3-4 of them, one 80 Dodge d100, 87 ramcharger and 2 c body ones, one for each of the 72 fury wagons
Click to expand...

Professor Fate said:
Do yourself a favor and put a new float on the old sending unit and reinstall it.
Your other option is to install a MeterMatch unit and hope you can get it calibrated decently.
Of course, you could order one from Australia, as they have the only manufacturer I've heard of with an accurate reproduction.
Fuel tank sending unit
Click to expand...

volaredon said:
Yup. All new aftermarket fuel sending units are made by the same outfit and reboxed and sold by many. I'm surprised Napa had it from any source. My son has bought at least 3-4 of them, one 80 Dodge d100, 87 ramcharger and 2 c body ones, one for each of the 72 fury wagons he's had. He finally got the current 72 reading right only after he put the NOS sending unit that I found for him into it. They all read empty when there's really a 1/2 tank of gas left. Every damn aftermarket one he's had. Pure garbage and lots of false hope for us guys playing with older cars
Click to expand...
Thanks, it’s a shame everything is Chinese junk nowadays. Cheers
 
I guess I'm just the lone ranger. I've used several Spectra sending units through the years, two very recently and none have read wrong. That's none. They are made in Canada. I've installed them in Mopars, General Motors products and Fords and every single one of them read correctly. The only thing I had to do to one, my Ford truck was adjust the float arm just a little. Other than that, they were install and go.
 
67cudaGuy said:
Thanks, it’s a shame everything is Chinese junk nowadays. Cheers
Click to expand...
There is an option. It isn't cheap though....
At FBBO, a member there posted links to retrofit EFI gas tanks that used different sending units that appeared to have a cylindrical type of float rather than the stock type that swings in an arc. These were supposed to read with greater accuracy.
 
I also have used spectra with 0 issues.
Question to OP:
Have you ohm checked the unit to ground (when installed) to make sure you don’t have a grounding issue?
Resistance will cause the reading to go weird. A buddy of mine had the same issue. He painted his tank straps and has put a rubber pad on top of the tank. And, no ground strap crossing the sender to the fuel line. His readings were all over the place.
Syleng1
 
RustyRatRod said:
I guess I'm just the lone ranger. I've used several Spectra sending units through the years, two very recently and none have read wrong. That's none. They are made in Canada. I've installed them in Mopars, General Motors products and Fords and every single one of them read correctly. The only thing I had to do to one, my Ford truck was adjust the float arm just a little. Other than that, they were install and go.
Click to expand...
Same here…until I got my 67 Barracuda. The rally dash gauge doesn’t work with the new sending units.
 
MidnightSwinger said:
Same here…until I got my 67 Barracuda. The rally dash gauge doesn’t work with the new sending units.
Click to expand...
I wonder what the difference in the gauge is? Or if there's one? I'm sure the resistance is the same.
 
RustyRatRod said:
I wonder what the difference in the gauge is? Or if there's one? I'm sure the resistance is the same.
Click to expand...
I’m trying to figure it out, but the same sending unit that worked for 3 different A bodies does some wonky stuff in the 67, the only difference being the Rally dash.
 
MidnightSwinger said:
I’m trying to figure it out, but the same sending unit that worked for 3 different A bodies does some wonky stuff in the 67, the only difference being the Rally dash.
Click to expand...
That would lead me to think it's the dash cluster somehow, but who knows?
 
RustyRatRod said:
That would lead me to think it's the dash cluster somehow, but who knows?
Click to expand...
You could be right, this is all French to me. I’ve got someone who knows more than me helping me with it, I’m upgrading the IVR and adding a Tach.

Hopefully it gets straightened around, that car didn’t come with the original sending unit so I’m SOL if I can’t figure it out. I’ll be damned if I’m going to spend $$$ on a NOS sending unit. I’ll just put gas in it every time I want to drive.
 
Have you grounded the wire to the sending unit? That should send the gauge to full.
 
RustyRatRod said:
I guess I'm just the lone ranger. I've used several Spectra sending units through the years, two very recently and none have read wrong. That's none. They are made in Canada. I've installed them in Mopars, General Motors products and Fords and every single one of them read correctly. The only thing I had to do to one, my Ford truck was adjust the float arm just a little. Other than that, they were install and go.
Click to expand...
That's exactly the experience I had with my unit also built by Spectra who also made my gas tank RRR.

No issues with mine either.
 
Syleng1 said:
I also have used spectra with 0 issues.
Question to OP:
Have you ohm checked the unit to ground (when installed) to make sure you don’t have a grounding issue?
Resistance will cause the reading to go weird. A buddy of mine had the same issue. He painted his tank straps and has put a rubber pad on top of the tank. And, no ground strap crossing the sender to the fuel line. His readings were all over the place.
Syleng1
Click to expand...
I did yes everything appears to be grounded properly.
 
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